Inyentor



Jan. 31, 1956 c. E. SIMPSON 2,732,769

SUPPORTING MEANS FOR A FIREARM BARREL Filed Feb. 10, 1955 INVENTOR.

ATTORNEYS Ellurenca E- .fiimpscul United States Patent SUPPORTING MEANS FOR A FIREARM BARREL Clarence E. Simpson, Wilbraham, Mass., assignor to the United States of America as represented by the Secretary of the Army Application February 10, 1953, Serial N6. 336,214

Claims. (31. 89-191) (Granted under Title 35, U. s. Code 1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to interchangeable barrels for automatic firearms and is more particularly directed to improved means for mounting the barrel.

It is desirable, oftentimes, in the operation of fully automatic firearms to replace an overheated barrel with one that is cold and unused in order to maintain the operational efficiency of the firearm. It is also desirable that the transfer of the barrels be performed as easily and expeditiously as possible.

It is, therefore, an object of this invention to provide an improved means of mounting a readily interchangeable barrel in automatic firearms.

It is a specific object of this invention to provide an interchangeable barrel for an automatic gas-operated firearm wherein means are provided for automatically aligning the gas port in the barrel with the corresponding port in the gas cylinder.

It is another specific object of this invention to provide a rotatable means of mounting a readably interchangeable barrel in automatic firearms whereby the barrel may be supportably moved during the mounting thereof in a wide range of directions so as to circuit interfering members of the firearm.

The specific nature of this invention as well as other objects and advantages thereof will clearly appear from a description of a perferred embodiment as shown in the accompanying drawings in which:

Fig. l is a fragmentary longitudinal sectional view of a firearm showing a barrel mounted by means of this invention; 7

Fig. 2 is a cross-sectional view taken along the line 2-2 of Fig. 1;

Fig. 3 is a front view of the firearm; and

Fig. 4 is a perspective view of the mounting member of this invention.

Illustrated in the drawings is a firearm having a gas cylinder 12 and a front support member 13 which extend forwardly from a receiver (not shown) in parallel relationship and which are joined adjacent the front ends thereof by a bracket 14. Centrally arranged in bracket 14 is a rotatably mounted spherical sleeve 15 having a bore 29 for slidably receiving the muzzle end of a barrel 16 which is detachably secured to the receiver (not shown).

Provided on barrel 16 is a bearing portion 17 arranged to slidably and rotatably engage bore 29 of sleeve 15. A longitudinal rectangular recess 18 in bearing portion 17 provides an enlarged orifice for communicating with a gas port 19 which extends therefrom into the bore of barrel 16. Gas port 19 is arranged to be aligned with a gas port 20 in gas cylinder 12 when barrel 16 is in locked position. One of a pair of diametrically opposed passageways 21 in sleeve 15 completes the communication between gas port 19 and gas port 20 when aligned therewith.

As has already been stated, sleeve 15 is substantially spherical in shape. To accommodate sleeve 15 in bracket 14, there is provided therethrough a cylindrical aperture 22 having spherically contoured walls which form a socket 23 arranged to matingly receive sleeve 15.

To install sleeves 15 in socket 23, bracket 14 is provided with a pair of oppositely disposed arcuate recesses 24 which extend rearwardly and communicate with socket 23 to permit entry of sleeve 15 when so turned that the longitudinal bore axis thereof is in parallel alignment with the vertical axis of socket 23. When fully aligned with socket 23, sleeve 15 is rotated to bring the bore axis thereof parallel with the longitudinal axis of the firearm.

Provided through one side of bracket 14, in alignment with the lateral axis of socket 23, is a hole 28 which accommodates a pin 25 having a spring locking tab 26 at one end which hooks resiliently over the forward edge of bracket 14. In the outer surface of sleeve 15, at right angles to the line drawn between passageways 21, there is a longitudinal elongated slot 27 adapted to be engaged by pin 25. The engagement of pin 25 with slot 27 permits limited rotation of sleeve 15 about the vertical axis between passageways 21 and also permits complete rotation about its lateral axis.

To replace barrel 16 by means of this invention, barrel 16 is rotatably unlocked from the receiver (not shown) with bearing portion 17 thereof turning freely in bore 29 of sleeve 15. Barrel 16 is next slid forwardly in sleeve 15, allowing the breech end thereof to disengage from the receiver. When barrel 16 is free of the receiver, the breech may be swung outwardly therefrom causing sleeve 15 to pivot in socket 23 about the vertical axis. Barrel 16 may then be withdrawn rearwardly out of engagement with sleeve 15 in a wide range of directions because of the rotatable mounting of sleeve 15. The new barrel 16 is installed by reversing the procedure. Because of the opposed passageways 21, it is not necessary for the operator to check the position of sleeve 15 when installing barrel 16 therein as either passageway 21 will complete the communication between gas port 19 in barrel 16 and gas port 20 in gas cylinder 12. Rectangular recess 18 in barrel 16 assures communication between gas port 19 and passageway 21, in event of variations in the mounting of different barrels.

Thus, it is obvious that there is here provided an improved means of mounting an interchangeable barrel in gas-operated firearms in which the transfer is aided by rotatable support of the muzzle end and which assures positive alignment of the cooperating gas ports in the barrel and gas cylinder.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. Means for releasably securing a barrel to a gasoperated firearm having a gas cylinder and a support member extending forwardly therefrom, said means comprising a bracket secured to the front end of said gas cylinder and support member, said bracket member constructed to pivotally receive a substantially shaped spherical sleeve and having a longitudinal bore therethrough to slidably receive said barrel, said sleeve being provided with a passageway arranged to permit the flow of gases therethrough from a gas port leading from said barrel into a gas port in said gas cylinder, and means permitting rotation of said sleeve when said passageway is in register with said gas ports of said barrel and cylinder and whereby said sleeve may be tilted to permit removal of said barrel therefrom when said barrel is unlocked from said receiver.

2. Means for releasably securing a barrel to a gas-operated firearm having a gas cylinder and a support member extending forwardly therefrom, said means comprising a bracket secured to the front ends of said gas cylinder and support member, said bracket member'having spherically contoured walls in the center portion thereof and terminating in a longitudinal cylindrical bore on each side therefrom constructed to receive a substantially shaped spherical sleeve therein, said sleeve being provided with a longitudinal bore to slidably receive said barrel, a passageway being provided in said sleeve extending from the outer periphery thereof to the bore therein arranged to permit the flow of gases therethrough from a gas port leading from said barrel into a gas port in said gas cylinder, said sleeve being also provided with an elongated slot on the outer periphery thereof positioned at right angles to said passageway and arranged to receive a pin therein thereby permitting limited rotation of said sleeve when said passageway is in register with said gas ports in said barrel and cylinder, said pin being slidably mounted in said bracket, and spring means for resiliently retaining said pin in said bracket and in engagement with said spherical sleeve.

3. In a gas-operated firearm having a receiver, a gas cylinder secured to the receiver and extending forwardly therefrom, a support member positioned below said gas cylinder and parallel therewith and being secured to the receiver, a bracket secured to the front ends of said gas cylinder and support member, socket means mounted in said bracket equi-distant between said cylinder and support having a longitudinal bore therethrough to slidably receive a barrel, said socket means being provided with a passageway arranged to permit the flow of gases therethrough from a gas port leading from said barrel into a gas port in said gas cylinder, and pivotal means permitting limited rotation of said socket means when said passage way is in register with said gas ports of said barrel and cylinder and whereby said socket means may be tilted to permit removal of said barrel therefrom when said barrel is unlocked from said receiver.

4. In a gas-operated firearm having a receiver, a gas cylinder secured to the receiver and extending forwardly therefrom, a support member positioned below said gas cylinder and parallel therewith and being secured to the receiver, a bracket secured to the front ends of said gas cylinder and support member, said bracket being provided with a spherical shaped formed recess in the center thereof constructed to receive a substantially shaped spherical sleeve therein, said sleeve having a longitudinally disposed bore to slidably receive a barrel, a passageway being provided in said sleeve extending from the outer periphery thereof to the bore therein, said cylinder and barrel being provided with gas ports in register with said passageway of said sleeve whereby gases from said barrel are permitted to flow into said gas cylinder through said passageway, said sleeve being provided with an elongated slot at right angles to said passageway on the outer periphery thereof arranged to receive a pin therein thereby permitting limited rotation of said sleeve when said passageway in said sleeve is in register with said gas ports of said barrel and cylinder, and spring means for resiliently retaining said pin in said bracket when said pin is in engagement with said spherical sleeve thereby permitting the tilting of said sleeve and barrel after said barrel has been unlocked from said receiver whereby said barrel may be removed rearwardly from said sleeve.

5. In a gas operated firearm having a replaceable barrel and a gas cylinder associated therewith, each having a mutually aligned gas port, the combination of a bracket secured to the front end of the gas cylinder and depending therefrom in the path of the muzzle end of the barrel, said bracket having a centrally disposed spherical socket portion communicating with a forwardly opening arcuate recess on either side of said socket portion, a spherical sleeve having an axial bore therethrough of sufficient diameter to form a zonal segment adapted to pass through the opening in said bracket formed by the combination of said socket portion and said communicating arcuate recesses when the longitudinal axis of said bore is vertically disposed, said sleeve being arranged to rotatably seat in said socket portion with said bore therein providing slidable passage for the muzzle end of the barrel, said sleeve having a symmetrically located pair of diametrically opposed holes and a slot in the exterior periphery thereof disposed substantially parallel to the longitudinal axis of said bore and at a point a quadrant length between said holes, and a pin projecting from said bracket into said socket portion to engage in said slot in said sleeve and thereby automatically position one of said holes in registry with the aligned gas ports of the barrel and gas cylinder when the former is fully assembled to the firearm, the engagement of said pin in said slot being also arranged to pre vent rotation of said sleeve about the longitudinal axis of said bore without interfering with the rotation thereof in the remaining directions whereby said sleeve provides a substantially universal bearing for pivoting the barrel about the muzzle end thereof during assembly to and disassembly from the firearm.

References Cited in the file of this patent UNITED STATES PATENTS 1,363,262 North Dec. 28, 1920 1,549,051 Schreiber Aug. 11, 1925 2,365,142 Turner Dec. 12, 1944 2,380,773 McMullen July 31, 1945 FOREIGN PATENTS 461,041 Great Britain Feb. 7, 1937 OTHER REFERENCES Page 14, Bild 5 of Einzelausbildung am M. G. 42, UP 

